Running Linux shell on OS X

I want some applications to run on my OS X. But they cant be ran due to they are only for Linux. How can I have a Linux shell on my OS X? I mean how can I have a seperate Linux shell and a OS X terminal on OS X?

To run GNU utilities (as found on Linux systems) alongside the mostly BSD-based OS X utilities on OS X, install them via Homebrew; note that installing alongside entails that the GNU utility names are g-prefixed to avoid shadowin the stock OS X utilities; e.g., GNU ls is installed as gls; also note that OS X's Bash is still v3.x: